Crucible and method of manufacture



W. A. DARRAH.

CRUCIBLE AND METHOD OF MANUFACTURE.

APPLICATION FILED Patented June 14, 1921.,

-E'IILZEAH 1%..iDAREtAEI,

@EUCIBLE @3510 i013 MANSFIELD, ill-EEG.

C91 Iiilililll'UFACTURE.

Application filed Jejrsary 3, 1918.

To all I rom concern:

Be it known that 1, WILLIAM A. Dnnnen, a citizen of the United States, residing at Mansfield, in the county of 'Richland and State of Qhio, have invented certain new and useful improvements in Crucibles and Methocls of Manufacture, oi which the following is a specification,

In the course of many metallurgical operotions it is necessary to have a supply of cheap and durable crucibles available of a type suitable for withstanding high tern- 'on relates to crucibles of this type and their method manufacture.

By of process described in this live -on it is possible to cheaply produce crucibles which, their struceure. will be very and yet he made in e very u cheer) insi er,

The crucibles, or staggers, are formed mostreadiiy by the so-ca led casting orocess and t applied crucibles and the iron: for

consists in mixing a 'l in rials with an at suitable clay, add e approxiiours (in l layer or clay harp 3 parts of colic crushed to "pass quart 1 inch sieve,

parts of alumina crushed to "h a 160 mesh sieve, finer,

e em.

above e clay that since s not more than i a, and 1 ually ofsilice, in above a J! l in pert GA tins inven- Serial 1%. Mi'hlil.

mixture is in the neighborhood of ten to fifteen per cent.

I have found that by the'cas'ting process the finer particles find their'wa-y to the surfaces next to the plaster of Paris, apparently carried there by the movement of the water in being absorbed by the walls of the mold. I find also that the mixture refelred to above will give crucibles and containers which are lined with line particles of carbon, alumina and the larger particles of carbon and alumina Will form the interior or supporting material for the walls of the crucibles.

The silica is so uniformly distributed throughout the materiel that while there is only ten per cent. in the entire body, the quantity at the surface is only a small raw tion of ten per cent. and is probably less than one or 'tvo pe cent.

Referring to the drawing, Figure 1 shows,

in section a portion of plastic material prepared by the method disclosed in this specification together with a section of a portion of the absorbent mold.

Fig. 2- shows a section of crucible pro duced by the process which forms the subject of this invention. Said crucible being cast in an absorhin mold having absorbent surfaces both Within the crucible and sun roundins its exterior.

Fig. 3 shows the s formed by this process ent mold surrounds the outside he cm cible only.

Referring to the figures, 1 indicates the plastic material; 5;? ind ates the larger refractory particles; indicates the smaller particles and indcates line oonglomerate and 5 indicates i non ebsorls est mold,

Crucible-s made in manner here de scribed are extrem ly ch p because of the small. eniount l l and are narticularly and becsuse of the absence of surface "the structure him no eet resisting and fire resist" on enter surfaces Where 1o req "1. The heavier iiusible materials which may o from the cur s-Orrin 1 Q naturally placed in th Where thei elono the charge which set in a very ole r is

. used as described above to place the heavier,

in'lusiblc materials in the center of the crucibles, leaving the finer material, which may be graphite, or any other substance desired on walls of the crucible. It will be apparent, therefore, that this allowsthe grading of the walls, both as to composition and size of particles. Since the finer materials always'go to the surface of the absorbing molds, it 18 possible to compose the surface of any material which 'may be selected and,

conversely, since the coarser materials remain in the center of the Wall, it is possible to have the center or I 'amc work composed of any, desired materials.

The process which is here described is most effectively carried out with crucibles of this nature although it should be understood that it is not confined to these crucibles as substantially the same results can be obtained by pressed crucibles made from materials containing little or no silica. It is essential, of course, in dealing with manganese, brass, etc., that the silica in the Walls be reduced to a minimum, however.

It should be understood, however, that the long life and high efficiency of crucibles made in this manner are decidedly advisable in carrying out my process.

It will be readily understood that after the crucibles have been used they will be destroyed and the walls and other portions could be re 'round and recast thus using the raw material practically indefinitely.

Having here described my invention, what I wish to secure by Letters Patent and claim as new is as follows:

1. The process of making crucibles which consists in mixing finely ground inert refractory, coarsely ground inert refractory and a colloidal binder, adding fluid until the mixture is liquid, pouring into a porous mold capable of absorbing said fluid and, after removing the mold, baking the prodnet.

2. A cast crucible having a wall composed of finely ground refractory material Oll ltS surface, coarsely groundrefractory in its interior, and a substantially uniform gradation in the size of the particles from the interior to the exterior.

3. A cast crucible having a wall composed of particles arranged according to size in a substantially uniform gradation from each surface toward the center.

4; A carbon Walled cast crucible having the surface of its walls composed of fine particles of carbon and aluminum, the in terior of its walls composed of larger particles of refractory materials and a substantially uniform graclationfi'om the exterior to the interior.

A plastic body having a graduated and varying composition throughout the thickness of the wall, said composition varying with the size of the particles in the dilferent portions of the wall.

6. A plastic body having a uniformly varying structure throughout its thickness, said structure varying in. such a manner that the site of the particles are greatest in the center and least at the outside Wall.

In testimony whereof I affix my signature.

WILLIAM it. Dachau. 

